Chapter 5 Flashcards
Enantiomer
A molecule that is not identical to its mirror image is a kind of stereoisomer. Have identical physical properties, such as melting point and boiling point, but differ in the direction in which their solutions rotate plane-polarized light.
Chiral
A molecule that is not identical to its mirror image.
Achiral
A molecule that has a plane of symmetry in any conformation must be identical to its mirror image and must be non……..
Chirality center
Tetrahedral carbon atom bonded to four different groups.
Optically active
The plane of polarization is rotated through an angle of an organic molecule.
Polarimeter
The angle of rotation can be measured with an instrument called…..
Levorotatory
Some optically active molecules rotate polarized light to the left (counterclockwise)…..(-)
Dextrorotatory
Some optically active molecules rotate polarized light to the right (clockwise)…..(+)
R Configuration
If a curved arrow drawn from the highest to second- highest to third-highest ranked substituent (1,2,3) is clockwise. We say that the chirality center has the…….
S configuration
If an arrow from (1,2,3) is counter clickwise, the chirality center has the…..
Optical rotation vs absolute configuration
Note that the sign of optical roation, (+) or(-) is not related to the R,S designation. There is no correlation.
Diastereomers
Stereoisomers that are not mirror images. relationship between two ……. is like that of hands from different people. they aren’t identical and they aren’t mirror images.
Enantiomers vs Diastereomers:
enantiomers have opposite configurations at all chirality centers, whereas diastereomers have opposite at some (one or more) chirality centers but the same configuration at others.
Epimers
In the special case where two diastereomers differ at only one chirality center but are the same at all others……
Meso compounds
Compounds, which are achiral, yet contain chirality centers, are called…..
They are different compounds all together with different physical properties and are not mirror images.
Racemic Mixture or racemate
50:50 mixture of the two chiral enantiomers. denoted by the symbol (+-) or the prefix d,l to indicate an equal mixture of dextrorotatory and levorotatory forms. Which equal to optical rotation.
Isomers
are compounds with the same chemical formula but different structures.
Constitutional Isomers
are compounds whose atoms are connected differently. Among the kinds we’ve seen are skeletal, functional and positional isomers.
Stereoisomers
Compounds whose atoms are connected in the same order but with a different spatial arrangement. Among the kinds we’ve seen are enantiomers, diastereomers, and cis-trans isomers of cycloalkanes. Cis-trans isomers are just a subclass of diastereomers because they are non-mirror image stereoisomers.
